add tests

Signed-off-by: bytemare <3641580+bytemare@users.noreply.github.com>

commitment.go

@@ -38,35 +38,6 @@ type Commitment struct {
  Group group.Group
 }
 
-// Validate returns an error if the commitment is
-func (c *Commitment) Validate(g group.Group) error {
- if c.Group != g {
- return fmt.Errorf(
- "commitment %d for participant %d has an unexpected ciphersuite: expected %s, got %s",
- c.CommitmentID,
- c.SignerID,
- g,
- c.Group,
- )
- }
-
- generator := g.Base()
-
- if c.HidingNonceCommitment == nil || c.HidingNonceCommitment.IsIdentity() ||
- c.HidingNonceCommitment.Equal(generator) == 1 {
- return fmt.Errorf("commitment %d for signer %d has an %w", c.CommitmentID,
- c.SignerID, errHidingNonceCommitment)
- }
-
- if c.BindingNonceCommitment == nil || c.BindingNonceCommitment.IsIdentity() ||
- c.BindingNonceCommitment.Equal(generator) == 1 {
- return fmt.Errorf("commitment %d for signer %d has an %w", c.CommitmentID,
- c.SignerID, errBindingNonceCommitment)
- }
-
- return nil
-}
-
 // Copy returns a new Commitment struct populated with the same values as the receiver.
 func (c *Commitment) Copy() *Commitment {
  return &Commitment{
@@ -90,8 +61,6 @@ type CommitmentList []*Commitment
 // a > b and zero when a == b.
 func cmpID(a, b *Commitment) int {
  switch {
- case a == nil || b == nil:
- return 0
  case a.SignerID < b.SignerID: // a < b
  return -1
  case a.SignerID > b.SignerID:
@@ -152,91 +121,6 @@ func (c CommitmentList) ParticipantsScalar() []*group.Scalar {
  })
 }
 
-func (c *Configuration) isSignerRegistered(sid uint64) bool {
- for _, peer := range c.SignerPublicKeys {
- if peer.ID == sid {
- return true
- }
- }
-
- return false
-}
-
-// ValidateCommitmentList returns an error if at least one of the following conditions is not met:
-// - list length is within [threshold;max]
-// - no signer identifier in commitments is 0
-// - no singer identifier in commitments is > max signers
-// - no duplicated in signer identifiers
-// - all commitment signer identifiers are registered in the configuration
-func (c *Configuration) ValidateCommitmentList(commitments CommitmentList) error {
- // Validate number of commitments.
- length := uint64(len(commitments))
-
- if length == 0 {
- return fmt.Errorf("commitment list is empty")
- }
-
- if length < c.Threshold {
- return fmt.Errorf("too few commitments: expected at least %d but got %d", c.Threshold, length)
- }
-
- if length > c.MaxSigners {
- return fmt.Errorf("too many commitments: expected %d or less but got %d", c.MaxSigners, length)
- }
-
- // set to detect duplication
- set := make(map[uint64]struct{}, length)
-
- for i, commitment := range commitments {
- if commitment == nil {
- return fmt.Errorf("the commitment list has a nil commitment")
- }
-
- if commitment.SignerID == 0 {
- return fmt.Errorf("signer identifier for commitment %d is 0", commitment.CommitmentID)
- }
-
- if commitment.SignerID > c.MaxSigners {
- return fmt.Errorf(
- "signer identifier %d for commitment %d is above allowed values (%d)",
- commitment.SignerID,
- commitment.CommitmentID,
- c.MaxSigners,
- )
- }
-
- // Check for duplicate participant entries.
- if _, exists := set[commitment.SignerID]; exists {
- return fmt.Errorf("commitment list contains multiple commitments of participant %d", commitment.SignerID)
- }
-
- set[commitment.SignerID] = struct{}{}
-
- // Check general validity of the commitment.
- if err := commitment.Validate(c.group); err != nil {
- return err
- }
-
- // List must be sorted, compare with the next commitment.
- if uint64(i) <= length-2 {
- if cmpID(commitment, commitments[i+1]) > 0 {
- return fmt.Errorf("commitment list is not sorted by signer identifiers")
- }
- }
-
- // Validate that all commitments come from registered signers.
- if !c.isSignerRegistered(commitment.SignerID) {
- return fmt.Errorf(
- "signer identifier %d for commitment %d is not registered in the configuration",
- commitment.SignerID,
- commitment.CommitmentID,
- )
- }
- }
-
- return nil
-}
-
 func (c CommitmentList) Encode() []byte {
  n := len(c)
  if n == 0 {
@@ -359,3 +243,128 @@ func (c CommitmentList) groupCommitment(bf BindingFactors) *group.Element {
 
  return gc
 }
+
+func (c *Configuration) isSignerRegistered(sid uint64) bool {
+ for _, peer := range c.SignerPublicKeys {
+ if peer.ID == sid {
+ return true
+ }
+ }
+
+ return false
+}
+
+// ValidateCommitment returns an error if the commitment is not valid.
+func (c *Configuration) ValidateCommitment(commitment *Commitment) error {
+ if commitment == nil {
+ return fmt.Errorf("the commitment list has a nil commitment")
+ }
+
+ if commitment.SignerID == 0 {
+ return fmt.Errorf("signer identifier for commitment %d is 0", commitment.CommitmentID)
+ }
+
+ if commitment.SignerID > c.MaxSigners {
+ return fmt.Errorf(
+ "signer identifier %d for commitment %d is above allowed values (%d)",
+ commitment.SignerID,
+ commitment.CommitmentID,
+ c.MaxSigners,
+ )
+ }
+
+ if commitment.Group != c.group {
+ return fmt.Errorf(
+ "commitment %d for participant %d has an unexpected ciphersuite: expected %s, got %d",
+ commitment.CommitmentID,
+ commitment.SignerID,
+ c.group,
+ commitment.Group,
+ )
+ }
+
+ generator := c.group.Base()
+
+ if commitment.HidingNonceCommitment == nil || commitment.HidingNonceCommitment.IsIdentity() ||
+ commitment.HidingNonceCommitment.Equal(generator) == 1 {
+ return fmt.Errorf("commitment %d for signer %d has an %w", commitment.CommitmentID,
+ commitment.SignerID, errHidingNonceCommitment)
+ }
+
+ if commitment.BindingNonceCommitment == nil || commitment.BindingNonceCommitment.IsIdentity() ||
+ commitment.BindingNonceCommitment.Equal(generator) == 1 {
+ return fmt.Errorf("commitment %d for signer %d has an %w", commitment.CommitmentID,
+ commitment.SignerID, errBindingNonceCommitment)
+ }
+
+ // Validate that the commitment comes from a registered signer.
+ if !c.isSignerRegistered(commitment.SignerID) {
+ return fmt.Errorf(
+ "signer identifier %d for commitment %d is not registered in the configuration",
+ commitment.SignerID,
+ commitment.CommitmentID,
+ )
+ }
+
+ return nil
+}
+
+func (c *Configuration) validateCommitmentListLength(commitments CommitmentList) error {
+ length := uint64(len(commitments))
+
+ if length == 0 {
+ return fmt.Errorf("commitment list is empty")
+ }
+
+ if length < c.Threshold {
+ return fmt.Errorf("too few commitments: expected at least %d but got %d", c.Threshold, length)
+ }
+
+ if length > c.MaxSigners {
+ return fmt.Errorf("too many commitments: expected %d or less but got %d", c.MaxSigners, length)
+ }
+
+ return nil
+}
+
+// ValidateCommitmentList returns an error if at least one of the following conditions is not met:
+// - list length is within [threshold;max]
+// - no signer identifier in commitments is 0
+// - no singer identifier in commitments is > max signers
+// - no duplicated in signer identifiers
+// - all commitment signer identifiers are registered in the configuration
+func (c *Configuration) ValidateCommitmentList(commitments CommitmentList) error {
+ if err := c.validateCommitmentListLength(commitments); err != nil {
+ return err
+ }
+
+ // set to detect duplication
+ set := make(map[uint64]struct{}, len(commitments))
+
+ for i, commitment := range commitments {
+ // Check general validity of the commitment.
+ if err := c.ValidateCommitment(commitment); err != nil {
+ return err
+ }
+
+ // Check for duplicate participant entries.
+ if _, exists := set[commitment.SignerID]; exists {
+ return fmt.Errorf("commitment list contains multiple commitments of participant %d", commitment.SignerID)
+ }
+
+ set[commitment.SignerID] = struct{}{}
+
+ // List must be sorted, compare with the next commitment.
+ if i <= len(commitments)-2 {
+ if commitments[i+1] == nil {
+ return fmt.Errorf("the commitment list has a nil commitment")
+ }
+
+ if cmpID(commitment, commitments[i+1]) > 0 {
+ return fmt.Errorf("commitment list is not sorted by signer identifiers")
+ }
+ }
+ }
+
+ return nil
+}

coordinator.go

@@ -58,8 +58,12 @@ func (c *Configuration) AggregateSignatures(
 
  // Aggregate signatures
  z := group.Group(c.Ciphersuite).NewScalar()
- for _, share := range sigShares {
- z.Add(share.SignatureShare)
+ for _, sigShare := range sigShares {
+ if err := c.validateSignatureShareLight(sigShare); err != nil {
+ return nil, err
+ }
+
+ z.Add(sigShare.SignatureShare)
  }
 
  signature := &Signature{
@@ -115,23 +119,13 @@ func (c *Configuration) PrepareSignatureShareVerification(message []byte,
  return groupCommitment, bindingFactors, participants, nil
 }
 
-func (c *Configuration) getSignerPubKey(id uint64) *group.Element {
- for _, pks := range c.SignerPublicKeys {
- if pks.ID == id {
- return pks.PublicKey
- }
- }
-
- return nil
-}
-
 func (c *Configuration) validateSignatureShareLight(sigShare *SignatureShare) error {
  if sigShare == nil {
  return errors.New("nil signature share")
  }
 
  if sigShare.SignatureShare == nil || sigShare.SignatureShare.IsZero() {
- return errors.New("invalid signature share (nil or zero)")
+ return errors.New("invalid signature share (nil or zero scalar)")
  }
 
  return nil
@@ -155,7 +149,7 @@ func (c *Configuration) validateSignatureShareExtensive(sigShare *SignatureShare
  }
 
  if sigShare.Group != c.group {
- return fmt.Errorf("signature share has invalid group parameter, want %s got %s", c.group, sigShare.Group)
+ return fmt.Errorf("signature share has invalid group parameter, want %s got %d", c.group, sigShare.Group)
  }
 
  if c.getSignerPubKey(sigShare.SignerIdentifier) == nil {

frost.go

@@ -216,6 +216,16 @@ func (c *Configuration) Init() error {
  return nil
 }
 
+func (c *Configuration) getSignerPubKey(id uint64) *group.Element {
+ for _, pks := range c.SignerPublicKeys {
+ if pks.ID == id {
+ return pks.PublicKey
+ }
+ }
+
+ return nil
+}
+
 func (c *Configuration) ValidateKeyShare(keyShare *KeyShare) error {
  if !c.verified {
  if err := c.Init(); err != nil {

signer.go

@@ -11,7 +11,6 @@ package frost
 import (
  "crypto/rand"
  "encoding/binary"
- "errors"
  "fmt"
 
  group "github.com/bytemare/crypto"
@@ -158,13 +157,6 @@ func (s *Signer) verifyNonces(com *Commitment) error {
 // VerifyCommitmentList checks for the Commitment list integrity and the signer's commitment. This function must not
 // return an error for Sign to succeed.
 func (s *Signer) VerifyCommitmentList(commitments CommitmentList) error {
- // Due diligence check that no signer id == 0.
- if s.KeyShare.ID == 0 {
- return errors.New("signer identifier is 0 (invalid)")
- }
-
- commitments.Sort()
-
  // Validate general consistency of the commitment list.
  if err := s.Configuration.ValidateCommitmentList(commitments); err != nil {
  return fmt.Errorf("invalid list of commitments: %w", err)